A cenventional ceramic heater comprising a ceramic substrate consists of an alumina substrate having a heat-generating pattern of tungsten- or molybdenum-containing paste formed thereon by metallizing. However, such a heater has a significant problem: when it is used at very high temperature (i.e., at least 1,000.degree. C.), the electrical resistance of the heating surface is increased because the metal on the surface is gradually diffused into the substrate. To solve this problem, it has been proposed to embed the tungsten- or molybdenum-heating element in the ceramic substrate. However, the resulting heater has low mechanical strength because the substrate has embedded therein a material that is foreign to that substrate; furthermore, it takes additionally several seconds for the surface of the heater to reach a predetermined temperature since there is required a period of time for heat generated by the heating element embeded in the heater to conduct to the surface of the heater.